The Investigation Of Electrochemical Sensor Based On Functionalized Graphene

In this paper, a series of novel molecularly imprinted electrochemical sensor based ongraphene oxide were constructed with high selectivity and specific identification. Realize withactual samples determination of high selectivity, high sensitivity and simple operation control.Mainly graphene oxide was functional, and then using molecular imprinting technique andself-assembly technology combined with drops of coating method, electrodeposition methodand sol-gel method built novel electrochemical workstation to determine carbendazim, dibutylphthalate, chloramphenicol, bisphenol A and other analysis, satisfactory results were obtained.The first part, magnetic nanoparticles generated on the surface of graphene oxide throughcoprecipitation role, then β-cyclodextrin and gold nanoparticles were compound byself-assembled, soβ-cyclodextrin/magnetic graphene/gold nanoparticle composites wereobtained, the preparative nanocomposite was comprehensive characterization by IR, XRD,TEM, SEM and so on. Using drops of coating and polymerization technology built the newcarbendazim molecularly imprinted electrochemical sensor based on functionalization ofgraphene, and the optimization of determination conditionss were obtained, such as theamount of coating, pH, scanning speed and the incubation time, etc. Establish a highselectivity and sensitivity analysis method for determination of carbendazim, the linear rangeof the method was5.0×109~5.0×106mol/L, detection limit was1.7×10-9mol/L, andsuccessfully appliy to the analysis of samples of carbendazim.The second part, the coprecipitation and self-assembly technology were used to preparethe β-cyclodextrin/magnetic graphene composite gold nanoparticles, and then phthalic aciddibutyl as template molecule, polymerization phthalic acid dibutyl molecularly imprintedpolymers was prepared by the method of precipitation, and the preparation of molecularlyimprinted polymer was characterized. The synthesis of molecularly imprinted polymerapplied to the electrochemical workstation to build the phthalic acid dibutyl-molecularimprinting-electrochemical sensor. And the performance characterization experiment of thesensor and optimization conditions of electrochemical determination were conducted. Studyanalytical and selective performance of the sensor under optimum conditions, by the availableexperimental results, linear range of the sensor was2.5×109~5.0×106mol/L, the detection limit was8.0×10-10mol/L. Realize high sensitive and specific identification test with samplesof phthalic acid dibutyl.The third part, using the modified Hummers method synthesis of graphene oxide, andmagnetic nanoparticles generated on the surface of graphene oxide by using ferric chlorideand ferric chloride through coprecipitation method, after silanization modification, themagnetic graphene oxide composite gold nanoparticles were obtained by self-assemblytechnology, with the method of drop these on the gold electrode surface, chloramphenicol astemplate molecule, molecularly imprinted membrane formed by sol-gel method, after elutingtemplate molecules get new chloramphenicol molecularly imprinted electrochemical sensor.The conditions of detecting chloramphenicol were optimized, and using the cyclicvoltammograms and electrochemical impedance spectroscopy charactered electrochemicalperformance of molecularly imprinted sensor. The experimental results showed that theproposed method integrated the high selectivity of molecularly imprinted technology with thehigh sensitivity of electrochemical sensors. Method of linear range was2.5×109~5.0×106mol/L, detection limit was8.0×1010mol/L, and successfully apply to the analysis and testingof actual samples.The fourth part, prepare the magnetic graphene oxide composite gold nanoparticles, andthen bisphenol A molecularly imprinted membrane formed through the sol-gel technology,after eluting template molecules, a new type of bisphenol A molecularly imprintedelectrochemical sensor was built based on graphene, and used for high sensitive and highselective analysis of the bisphenol A sample. And the performance characterizationexperiment of the sensor and optimization conditions of electrochemical determination wereconducted. Experimental results showed that the linear range of molecularly imprintedelectrochemical sensor developed for the determination bisphenol A was5.0×10-7~1.0×10-4mol/L, the detection limit was8.1×10-8mol/L, and apply to the analysis of actual samples andsatisfied results were obtained.